ABOVE: A blue shark (Prionace glauca)
KEITH HISCOCK
The oceans are losing their oxygen. Warmer waters and excess nutrients from human activities have led to a 2 percent decline in the seas’ oxygen levels since the 1960s—and it’s taking a toll on marine life. In a study published January 19 in eLife, researchers find that blue sharks (Prionace glauca) don’t dive as deeply in low-oxygen areas, a behavior that could leave them more vulnerable to fishing.
“I think [the study] is important for a couple of reasons. It draws attention to the problem of ocean deoxygenation, which isn’t very widely known, and it draws attention to sharks, which people don’t often think about as being vulnerable to climate change,” says Lisa Levin, a biological oceanographer at the Scripps Institution of Oceanography who was not involved in the study. “It brings together changes in distributions of [sharks] with the consequences of fishing ...
